Can you please explain the answer a bit more. "Pack all the buttons in it" ... here button means checkbutton ...right ? And you want me to create a 'up' and 'down' button beside each of those checkbuttons in each row ?
Currently I am running the following code. If you just look at it,it will help you to explain me a bit elaborately

This was really helpful. I was also thinking of using hash for storing and re-positioning the text items upon clicking on up and down button. I proceeded as below but a bit stuck. Let us assume I have put your code in a subroutine called build_layout()

Note that I've added hash %is_selected for the Checkbuttons to have a 'memory' ( $is_selected{$item} will tell you whether the given item is required ). The moving of Buttons is achieved with manipulating the list itself (no hash necessary for that):